Integrated optical device

ABSTRACT

An improved integrated optical device ( 5   a - 5   g ) is disclosed containing first and second devices ( 10   a - 10   g   ; 15   a   , 15   e ), optically coupled to each other and formed in first and second different material systems. One of the first or second devices ( 10   a - 10   g   , 15   a,    15   e ) has a Quantum Well Intermixed (QWI) region ( 20   a,    20   g ) at or adjacent a coupling region between the first and second devices ( 10   a - 10   g   ; 15   a,    15   e ). The first material system may be a Ill-V semiconductor based on Gallium Arsenide (GaAs) or Indium Phosphide (InP), while the second material may be Silica (SiO 2 ), Silicon (Si), Lithium Niobate (LiNbO 3 ), a polymer, or glass.

FIELD OF INVENTION

[0001] This invention relates to an improved integrated optical deviceor optoelectronic device, and particularly to hybrid integration ofdevices formed in different material systems. For example, hybridintegration of III-V semiconductor devices with passive waveguidestructures.

BACKGROUND TO INVENTION

[0002] Hybrid integration of III-V semiconductor components with passivewaveguides is of increasing importance as a method of increasing thefunctionality of integrated optical and photonic systems. Applicationsinclude: optical communication systems, optical sensing applications,and optical data processing.

[0003] A fundamental problem in hybrid integration is that thesemiconductor element has a higher refractive index than the passivewaveguide. In the case of a III-V semiconductor component integrated ona planar Silica (SiO₂) platform, the refractive indices are typicallyaround 3.6 for the semiconductor and 1.5 for the Silica. This refractiveindex difference causes a number of problems, e.g. there is a highreflection coefficient at the interface between the two devices, and themode size in each device is different. Both of these effects result in aloss in optical power, reduced coupling efficiency between the twodevices, and scattering of light, and undesirable reflections.

[0004] It is an object of the present invention to obviate or at leastmitigate one or more of the aforementioned problems in the prior art.

[0005] Further objects of various embodiments of the present inventioninclude:

[0006] enablement of hybrid integration to be carried out, whileensuring good mode matching between active and passive sections;

[0007] ease of manufacture;

[0008] low loss coupling between active and passive sections.

SUMMARY OF INVENTION

[0009] According to a first aspect of the present invention there isprovided an integrated optical device including first and second devicesoptically coupled one to the other and formed in first and seconddifferent material systems, at least one of the first or second deviceshaving a Quantum Well Intermixed (QWI) region at or adjacent a couplingregion between the first and second devices.

[0010] Quantum Well Intermixing (QWI) permits a postgrowth modificationto the absorption edge of Multiple-Quantum Well (MQW) material, andtherefore provides a flexible, reliable, simple, and low-cost approachcompared to competing integration schemes such as selective area epitaxyor selective etching and regrowth.

[0011] Quantum Well Intermixing (QWI) provides a means of tuning anabsorption band edge controllably in Quantum Well (QW) structures, andmay be utilized to fabricate low-loss optical interconnects betweenmonolithically integrated optical devices or integrated optoelectronicdevices.

[0012] The first material system may be a III-V semiconductor materialsystem. The III-V semiconductor material may be selected from or includeone or more of: Gallium Arsenide (GaAs), Aluminium Gallium Arsenide(AlGaAs), Indium Phosphide (InP), Gallium Arsenide Phosphide (GaAsP),Aluminium Gallium Arsenide Phosphide (AlGaAsP), Indium Gallium ArsenidePhosphide (InGaAsP), or the like.

[0013] The second material system may be a non III-V semiconductormaterial. The second material system may be selected from: Silica(SiO₂), Silicon (Si), Lithium Niobate (LiNbO₃), a polymer, a glass, orthe like, any of which may be doped with optically active material.

[0014] The first device may be or include an active device component,such as a laser diode, light emitting diode (LED), optical modulator,optical amplifier, optical switch, or switching element, opticaldetector (eg photodiode), or the like. The first device may also includea passive device compound such as a passive waveguide.

[0015] The second device may be, or include a passive component such asa passive waveguide.

[0016] Preferably, the coupling region provides means for at leastsubstantially mode matching between the first and second devices.

[0017] In one arrangement the first device provides the Quantum WellIntermixed (QWI) region.

[0018] In the one arrangement the mode matching means may comprise awaveguide provided in the first device which waveguide may be a“tapered” waveguide providing a linear change in width, a non-linearchange in width, and/or a “periodic” or “a-periodic” segmentation.

[0019] Preferably, the coupling region provides anti-reflection means ator near an interface between the first and second devices.

[0020] The anti-reflection means may comprise or include ananti-reflection coating on a facet of the first device provided at theinterface between the first and second devices.

[0021] The anti-reflection means may also comprise or include facets ofthe first and second devices provided at the interface between the firstand second devices, the facets being formed at an (acute) angle to anintended direction of optical transmission. The facets may therefore bereferred to as “angled facets”.

[0022] In a preferred embodiment a first waveguide section in the firstdevice and preferably also a second waveguide section in the seconddevice is/are bent.

[0023] The integrated optical device may be adapted to operate in awavelength region of about 600 to 1300 nm or of about 1200 to 1700 nm.

[0024] According to a second aspect of the present invention, there isprovided an integrated optical circuit, optoelectronic integratedcircuit, or photonic integrated circuit including at least oneintegrated optical device according to the first aspect of the presentinvention.

[0025] According to a third aspect of the present invention there isprovided an apparatus including at least one integrated optical device,the at least one integrated optical device providing first and seconddevices optically coupled one to the other and formed in first andsecond different material systems, one of the first or second deviceshaving a Quantum Well Intermixed (QWI) region at or adjacent a couplingregion between the first and second devices.

[0026] According to a fourth aspect of the present invention there isprovided a method of providing an integrated optical device havinghybrid integration of first and second devices formed in first andsecond different material systems comprising:

[0027] providing one of the first or second devices with a Quantum WellIntermixed (QWI) region at or adjacent a coupling region between thefirst and second devices.

[0028] The Quantum Well Intermixed (QWI) region may be formed from anumber of techniques, but preferably by a universal damage inducedtechnique, Impurity Free Vacancy Diffusion (IFVD).

[0029] In a preferred embodiment, the Quantum Well Intermixed (QWI)region may be formed in the first device by intermixing a QuantumWell(s) (QW) in a core optical guiding layer of the first device, e.g.by Impurity Free Vacancy Diffusion (IFVD).

[0030] When performing IFVD, a dielectric, e.g. SiO₂ layer or film, maybe deposited upon a top cap layer of the a III-V semiconductor materialof the first device. Subsequent rapid thermal annealing of thesemiconductor material causes bonds to break within the semiconductoralloy, e.g. Gallium ions or atoms which are susceptible to Silica(SiO₂), to dissolve into the Silica so as to leave vacancies in the caplayer. The vacancies then diffuse through the semiconductor materialinducing layer intermixing, e.g. in the Quantum Well(s) (QW).

[0031] IFVD has been reported in “Quantitative Model for the Kinetics OfCompositional Intermixing in GaAs—AlGaAs Quantum—ConfinedHeterostructures,” by Helmy et al, IEEE Journal of Selected Topics inQuantum Electronics, Vol. 4, No. 4, July/August 1998, pp. 653 - 660, thecontent of which is incorporated herein by reference.

[0032] According to a fifth aspect of the present invention there isprovided a first device according to the first aspect of the presentinvention.

BRIEF DESCRIPTION OF DRAWINGS

[0033] Embodiments of the present invention will now be described, byway of example only, and with reference to the accompanying diagrams,which are:

[0034]FIG. 1(a) a schematic plan view of a first semiconductor chipintegrated with a passive photonic integrated circuit (PIC) according toa first embodiment of the present invention;

[0035]FIG. 1(b)-(d) schematic plan views of second, third and fourthsemiconductor chips integratable with a passive photonic integratedcircuit (PIC) similar to or the same as that of FIG. 1(a) according tothe present invention;

[0036]FIG. 2(a) a schematic plan view of a fifth semiconductor chipaccording to the present invention;

[0037]FIG. 2(b) a schematic plan view of the fifth semiconductor chip ofFIG. 2(a) integrated with a passive photonic integrated circuit (PIC)according to a fifth embodiment of the present invention;

[0038]FIG. 3 a schematic cross-sectional end view showing a possiblelayer structure of a semiconductor chip according to a sixth embodimentof the present invention;

[0039]FIG. 4 a schematic perspective view from one end, above and to oneside of the semiconductor chip of FIG. 3;

[0040]FIG. 5 a schematic perspective view from one end, above and to oneside of a semiconductor chip according to a seventh embodiment of thepresent invention.

DETAILED DESCRIPTION

[0041] Referring initially to FIG. 1(a) there is illustrated anintegrated optical device, generally designated 5 a, according to afirst embodiment of the present invention and providing the first andsecond devices 10 a, 15 a respectively, the first and second devices 10a, 15 a being optically coupled one to the other and formed in first andsecond dis-similar material systems, at least one of the first or seconddevices 10 a, 15 a having a Quantum Well Intermixed (QWI) region 20 a ator adjacent a coupling region 21 a between the first and second devices10 a, 15 a.

[0042] In this embodiment the first materials system is a III-Vsemiconductor material system based on either Gallium Arsenide (GaAs) orIndium Phosphide (InP). For example the Ill-V semiconductor material maybe selected or include one or more of: Gallium Arsenide (GaAs),Aluminium Gallium Arsenide (AlGaAs), and Indium Phosphide (InP), GalliumArsenide Phosphide (GaAsP), Aluminium Gallium Arsenide Phosphide(AlGaAsP), Indium Gallium Arsenide Phosphide (InGaAsP), or the like. Theintegrated optical device 5 a may therefore be adapted to operate in theso-called “short” wavelength region of 600 to 1300 nm, or the so-called“long” wavelength region of 1200 to 1700 nm.

[0043] The second material system is a non Ill-V semiconductor materialand can be selected from Silica (SiO₂), Silicon (Si), Lithium Niobate(LiNbO₃), a polymer, glass or the like.

[0044] The first device 10 a comprises an active device component 22 a,selected from a laser diode, light emitting diode (LED), opticalmodulator, optical amplifier, optical switching element, opticaldetector (eg photodiode), or the like. The active device component 22 ais spaced from the Quantum Well Intermixed (QWI) region 20 a, the activedevice component 22 a, and passive QWI region 20 a being in opticalcommunication one with the other via a waveguide 23 a such as a ridgewaveguide.

[0045] The second device 15 a in this embodiment includes a passivedevice component in the form of a passive waveguide 16 a.

[0046] The coupling region 21 a provides anti-reflection means at ornear an interface between the first and second devices 10 a, 15 a. Theanti-reflection means comprise anti-reflection coating 25 a on an endfacet on first device 10 a provided at the interface between the firstand second devices 10 a, 15 a.

[0047] In a modification the anti-reflection means may also comprisefacets of the first and second devices 10 a, 15 a provided at theinterface between the first and second devices 10 a, 15 a, the facetsbeing formed at an acute angle to the intended direction of the opticaltransmission along waveguides 23 a, 16 a. In such a modification thefacets may be referred to as “angled facets”.

[0048] Referring now to FIG. 1(b) there is illustrated a secondembodiment of a first device 10 b comprising part of an opticallyintegrated device according to the present invention, like parts of thedevice 10 b being identified by the same numerals as those for the firstembodiment, but suffixed “b”. In this second embodiment the waveguide 23b includes a curved portion 30 b so as to improve optical couplingbetween the first device 10 b and a second device (not shown), byreduction of reflections at the interface between the first device 10 band the second device.

[0049] Referring now to FIG. 1(c), there is illustrated a thirdembodiment of a first device, generally designated 10 c, which may be apart of an optically integrated device according to an embodiment of apresent invention. The device 10 c is similar to the device 10 a of thefirst embodiment, and like parts are identified by like numerals, butsuffixed “c”. However, as can be seen from FIG. 1(c), the waveguide 23 cincludes at an end adjacent the coupling region to the second device(not shown) a tapered region 30 c which, in use, causes an optical mode“M” transmitted along the waveguide 23 c to expand as it traverses theoptical waveguide 23 c and is output from the first device 10 c from thetapered region 30 c. The converse of course applies for optical couplingto the first device 10 c from the second device (not shown).

[0050] Referring now to FIG. 1(d), there is shown a fourth embodiment ofa first device 10 d comprising part of an optically integrated deviceaccording to an embodiment of the present invention. The first device 10d is substantially similar to the device 10 a of the first embodiment,like parts being identified by like numerals but suffixed “d”. However,in the first device 10 d, the waveguide 23 d includes at an end adjacenta coupling region to a second device (not shown) a curved and taperedregion 30 b. The first device 10 d therefore combines the features ofthe embodiments of FIGS. 1(b) and (c).

[0051] It will be appreciated that in order to control electrically thefirst devices 10 a-10 d, an electrical contact (metalisation) will befabricated on a surface of the waveguide 23 a-23 d, while a furtherelectrical contact (metalisation) will be provided on an opposingsurface of the device 10 a-10 b.

[0052] It will be appreciated that the modifications shown in thesecond, third and fourth embodiments 10 b, 10 c, 10 d, seek to improveoptical coupling between the first device 10 b, 10 c, 10 d, and a seconddevice (not shown).

[0053] It will also be appreciated that the intermixed region 20 a to 20b acts to prevent, or at least reduce, optical absorption in theintermixed region 20 a-20 d adjacent to the coupling region 21 a-21 d.This is particularly so in the curved tapered waveguide section 30 b.

[0054] It will further be appreciated that although herein above thewaveguide sections 30 c and 30 d have been referred to as “tapered”regions, the optical mode transmitted therein towards an end of thefirst device 10 c to 10 d adjacent to second device (not shown) actuallyflares.

[0055] Referring now to FIGS. 2(a) and (b), there is illustrated anintegrated optical device generally designated 5 e, according to a fifthembodiment of the present invention. The device 5 e provides first andsecond devices 10 e, 15 e optically coupled one to the other and formedin first and second different material systems, the first device 10 ehaving a Quantum Well Intermixed (QWI) region 20 e adjacent a couplingregion 21 e between the first and second device 10 e, 15 e. As can beseen from FIGS. 2(a) and (b) a waveguide 23 e of the first device 10 ecomprises a tapered curved region 30 e adjacent a coupling region 21 ebetween the first and second devices 10 e, 15 e. Further, ananti-reflection coating 25 e is provided within the coupling region 21 eon an end facet of the first device 10 e. Also, a passive waveguide 16 eof the second device 15 e is complementarily curved to the portion 30 eso as to also assist in optical coupling between the first and seconddevices 10 e, 15 e.

[0056] Referring now to FIGS. 3 and 4, there is illustrated a sixthembodiment of a first device generally designated 10 f according to thepresent invention. Like parts of the device 10 f are identified by thesame numerals as for the device 10 a of the first embodiment of FIG.1(a) , but suffixed “f.”

[0057] The device 10 f comprises a GaAs substrate 50 f, upon which aregrown a number of epitaxial layers by known growth techniques such asMolecular Beam Epitaxy (MBE) or Metal Organic Chemical Vapour Deposition(MOCVD). The layers comprise a first 0.51 μm to 1 μm n-dopedAl_(0.50)Ga_(0.50)As layer 55 f, a second 5 μm n-dopedAl_(0.40)Ga_(0.60)As layer 60 f, a third 0.5 μm substantially intrinsicAl_(0.20)Ga_(0.80)As core layer, including a 10 nm GaAs Quantum Well(QW), 70 f as grown. On the core layer 65 f is grown a 1 μm p-dopedAl_(0.40)Ga_(0.60)As layer 75 f, and finally on that layer is grown a p+doped GaAs capping contact layer 80 f. As can be seen from FIG. 3, aridge waveguide 23 f is formed in the layers 75 f, 80 f by knownphotolithographic techniques. Further in this embodiment, a secondbroader ridge or mesa 35 f is also formed in the layers 65 f and 60 f.Thus the ridge waveguide 23 f comprises a primary waveguide while themesa 35 f comprises a secondary waveguide. The device 10 f also includesa tapered region 30 f on the waveguide 23 f. The device 10 f, therefore,acts as a mode converter converting a mode from the device 10 f coupledto a second device (not shown), or a mode transmitted from the seconddevice to the first device 10 f.

[0058] As can be seen from FIG. 3, contact metallisations 40 f and 45 fmay be provided on a top of ridge 23 f and an opposing surface of thesubstrate 50 f. Further, as can be seen from FIG. 4, the device 10 fincludes a Quantum Well Intermixed (QWI) region 20 f adjacent to the endof the device corresponding to the tapered region 30 f.

[0059] In this embodiment the Quantum Well Intermixed (QWI) region 20 fis formed in the first device 10 f by intermixing the Quantum Well 70 fin the layer 60 f within the region 20 f by Impurity Free VacancyDiffuision (IFVD). When performing IFVD upon a top cap layer 80 f of theIII-V semiconductor material comprising the first device 10 f, there isdeposited a dielectric, e.g. Silica (SiO₂), layer of film. Subsequentrapid thermal healing of the semiconductor material causes bonds tobreak within the semiconductor alloy and e.g. Gallium ions oratoms—which are susceptible to Silica (SiO₂)—to dissolve into the Silicaso as to leave vacancies in the cap layer 80 f. The vacancies thendiffuse through the semiconductor material inducing layer intermixing,e.g. in the Quantum Well 70 f.

[0060] Referring now to FIG. 5 and to Table 1, there is illustrated aseventh embodiment of a first device generally designated 10 g, for usein an optically integrated device according to the present invention. Inthis sixth embodiment, the first device 10 g is fabricated in IndiumGallium Arsenide Phosphide (In In_(1-x) Ga_(x) As_(y) P_(1-y)).

[0061] The layer structure, grown on an Indium Phosphide (InP) substrate50 g, is shown in Table 1 below. TABLE I Thickness Repeats (A) Materialx y Dopant Type 1 1000 In(x)GaAs 0.53 Zn p 1 500 Q1/18 Zn p 1 11500 InPp 1 50 Q1.05 i 1 2500 InP 1 800 Q1.1 i 1 500 QI.8 i  5* 120 Q1.26 i  5*65 In(x)GaAs 0.53 i 1 120 Q1.26 i 1 500 Q1.18 i 1 800 Q1.1 i 1 50000Q1.05 Si n 1 10000 InP (buffer Si n layer adjacent substate)

[0062] As can be seen from FIG. 5, the first device 10 g includes anactive waveguide 23 g and adjacent to coupling region to a second device(not shown) a tapered region 30 g. The waveguide 23 g comprises aprimary waveguide of the first device 10 g, while a further ridge ormesa 35 g formed on the device 10 g comprises a secondary waveguide. Inuse, the optical radiation generated within or transmitted from thewaveguide 23 g towards the tapered region 30 g as an optical mode, iscaused upon transmission through region 30 g from primary opticalguiding layer 65 g into layer 60 g for optical coupling to second device(not shown).

[0063] The first devices 10 f and 10 g illustrate a design ofregrowth-free tapered waveguide coupler. The small rib waveguide 23 f,23 g is located on top of a thick lower cladding layer 60 f, 60 g thatis partially etched to form mesa wave guide 35 f, 35 g. When the smallrib 23 f, 23 g is sufficiently wide, the fundamental optical mode isconfined to the small rib 23 f, 23 g, and there is a high confinement oflight within the undoped waveguide core layer 65 f, 65 g (which itselfcontains the active Quantum Well layers, e.g. 75 f in FIG. 3, orintermixed region 20 f, 20 g). At the other extreme, when the small rib23 f, 23 g is sufficiently narrow, the fundamental mode expands to fillthe larger mesa waveguide 35 f, 35 g. This behaviour is a consequence ofthe design of the waveguide layers. The thicknesses and compositions ofthe Quantum Well layers at the top of the mesa 35 f, 35 g, and extendingunder the small rib 23 f, 23 g are such as to prevent guiding of lightwithin these layers if the upper layers comprising the small rib 23 f,23 g are etched away. The resulting waveguide allows-separateoptimisation of the optical mode properties of the rib 23 f, 23 g andmesa 35 f, 35 g waveguides at the two extremes of rib width. At largerib widths high-performance device action (such as opticalamplification, optical detection, electro-absorptive orelectro-refractive modulation) can be achieved. At small rib widths thedimensions of the large mesa 35 f, 35 g and thickness of the lowercladding materials establish the optical mode size of the mesa waveguidefor optimum coupling to passive Silica waveguides. The expanded mode canbe designed for optimum coupling directly to single mode waveguides inthe second (non-semiconductor) material or to optical fibre, including1.3 μm and 1.5 μm telecommunication fibre.

[0064] The layer structure shown in FIG. 3 would be used to make a firstdevice 10 f with Quantum Wells resonant with radiation at a wavelengthof around 860 nm. The structure shown in FIG. 5 would be used to make afirst device 10 g with Quantum Wells resonant with radiation at awavelength around 1.5 μm.

[0065] It will be appreciated that the embodiments of the inventionhereinbefore described are given by way of example only, and are notmeant to limit the scope thereof in any way.

[0066] It will he particularly understood that the device of the presentinvention is easier and simpler to manufacture than other devices, andtherefore provides the potential of obtaining high quality devices atreduced cost.

[0067] It will also be appreciated that in the disclosed embodiments themode matching means comprised a “tapered” waveguide providing a linearor non-linear change in width, in modified implementations the change inwidth may be “periodically” or “a-periodically” segmented. Theexpression “segmented waveguide” is intended to encompass any waveguideinto which has been introduced a disturbance or variation in therefractive index of the waveguide along at least one dimension of thewaveguide. The variation may be periodic or, more preferably, aperiodic.Preferably the variation is along the longitudinal axis of thewaveguide. However, variations along the lateral axis, or even along anaxis oblique to the longitudinal axis may be used.

[0068] It will further be understood that in this invention, QuantumWell Intermixing (QWI) is used to reduce absorption by the Quantum Welllayers within the taper region and so reduce optical losses in the taperregion and improve device efficiency.

[0069] Finally, it will be appreciated that in a modification the firstdevice may be inverted with respect to the second device, i.e. the ridgewaveguide of the first device may be in contact with, or adjacent, asurface of the second device.

What is claimed is:
 1. An integrated optical device comprising a firstdevice formed in a first material system and a second device formed in asecond material system different from the first material system, saidsecond device optically coupled to the first device through a couplingregion, and said first device comprising a Quantum Well Intermixedregion.
 2. The integrated optical device of claim 1, wherein the QuantumWell Intermixed region is located adjacent to the coupling region.
 3. Anintegrated optical device comprising a first device formed in a firstmaterial system and a second device formed in a second material systemdifferent from the first material system, said second device opticallycoupled to the first device through a coupling region and comprising aQuantum Well Intermixed region.
 4. The integrated optical device ofclaim 3, wherein the Quantum Well Intermixed region is located adjacentto the coupling region.
 5. The integrated optical device of claim 1,wherein the first material system is a III-V semiconductor material. 6.The integrated optical device of claim 5, wherein the Ill-Vsemiconductor material comprises a material selected from the groupcomprising: Gallium Arsenide (GaAs), Aluminium Gallium Arsenide(AlGaAs), Indium Phosphide (InP), Gallium Arsenide Phosphide (GaAsP),Aluminum Gallium Arsenide Phosphide (AlGaAsP), or Indium GalliumArsenide Phosphide (InGaAsP).
 7. The integrated optical device of claim1, wherein the second material system comprises a material selected fromthe group comprising: Silica (SiO₂), Silicon (Si), Lithium Niobate(LiNbO₃), a polymer, or glass.
 8. The integrated optical device of claim1, wherein the second material system comprises an optically activematerial.
 9. The integrated optical device of claim 1, wherein the firstdevice comprises an optically active device.
 10. The integrated opticaldevice of claim 9, wherein the optically active device comprises adevice selected from the group comprising: a laser diode, a lightemitting diode (LED), an optical modulator, an optical amplifier, anoptical switch, or an optical detector.
 11. The integrated opticaldevice of claim 1, wherein the first device comprises an opticallypassive component.
 12. The integrated optical device of claim 1, whereinthe second device comprises an optically passive component.
 13. Theintegrated optical device of claim 11, wherein the optically passivecomponent comprises a passive waveguide.
 14. The integrated opticaldevice of claim 12, wherein the optically passive component comprises apassive waveguide.
 15. The integrated optical device of claim 1, whereinthe coupling region comprises means for at least substantial modematching between the first and second devices.
 16. The integratedoptical device of claim 15, wherein the means for mode matchingcomprises a waveguide located in the first device.
 17. The integratedoptical device of claim 16, wherein the waveguide is tapered.
 18. Theintegrated optical device of claim 16, wherein the waveguide ischaracterized by a linear change in width.
 19. The integrated opticaldevice of claim 16, wherein the waveguide is characterized by anon-linear change in width.
 20. The integrated optical device of claim16, wherein the waveguide is characterized by a periodic segmentation.21. The integrated optical device of claim 16, wherein the waveguide ischaracterized by an a-periodic segmentation.
 22. The integrated opticaldevice of claim 1, wherein the coupling region comprises anti-reflectionmeans.
 23. The integrated optical device of claim 22, wherein theanti-reflection means comprises an anti-reflection coating on a facet ofthe first device, said facet facing the second device.
 24. Theintegrated optical device of claim 22, wherein the anti-reflection meanscomprises a facet of the first device and a facet of the second device,said facets facing each other and positioned at an angle to an intendeddirection of optical transmission.
 25. The integrated optical device ofclaim 1, wherein the first device comprises a curved waveguide section.26. The integrated optical device of claim 1, wherein the second devicecomprises a curved waveguide section.
 27. The integrated optical deviceof claim 1 adapted to operate in a wavelength region of about 600 toabout 1300 nm.
 28. The integrated optical device of claim 1 adapted tooperate in a wavelength region of about 1200 to about 1700 nm.
 29. Anintegrated optical circuit comprising the integrated optical device ofclaim
 1. 30. An optoelectronic integrated circuit comprising theintegrated optical device of claim
 1. 31. A photonic integrated circuitincluding the integrated optical device of claim
 1. 32. An integratedoptical circuit comprising the integrated optical device of claim
 2. 33.An optoelectronic integrated circuit comprising the integrated opticaldevice of claim
 2. 34. A photonic integrated circuit including theintegrated optical device of claim
 2. 35. A method of manufacturing anintegrated optical device comprising the steps of: forming a firstdevice in a first material system; forming a Quantum Well Intermixedregion in the first device; forming a second device in a second materialsystem different from the first material system; and providing hybridintegration of the first and the second devices through a couplingregion.
 36. The method of manufacturing of claim 35, wherein the stepsof forming a Quantum Well Intermixed region in the first device andproviding hybrid integration of the first and the second devices througha coupling region are performed so that the Quantum Well Intermixedregion is located adjacent to the coupling region.
 37. A method ofmanufacturing an integrated optical device comprising the steps of:forming a first device in a first material system; forming a seconddevice in a second material system different from the first materialsystem; forming a Quantum Well Intermixed region in the second device;and providing hybrid integration of the first and the second devicesthrough a coupling region.
 38. The method of manufacturing of claim 37,wherein the steps of forming a Quantum Well Intermixed region in thesecond device and providing hybrid integration of the first and thesecond devices through a coupling region are performed so that theQuantum Well Intermixed region is located adjacent to the couplingregion.
 39. The method of claim 35, wherein the Quantum Well Intermixedregion is formed by the steps of: depositing on a surface of the firstdevice a dielectric layer; and annealing the first device.
 40. Themethod of claim 39, further comprising the step of removing thedielectric layer.